The present invention relates to a new and distinct variety of Buddleja davidii (butterfly bush) grown as an ornamental shrub for home and commercial landscapes. Butterfly bush is typically grown for its attractive, fragrant flowers that are borne throughout the growing season.
The new and distinct variety of butterfly bush resulted from a formal breeding program established by the inventors in Raleigh, N.C. United States. One of the objectives of the breeding program was to develop a compact, spreading Buddleja with blue flower color. ‘Blue Chip’ originated as a third generation descendant from a hand pollinated cross of ‘Honeycomb’×(‘Nanho Purple’×Buddleja lindleyana) made in 2001. ‘Honeycomb’ (unpatented) was released in 1997, and is described as a hybrid of Buddleja davidii and Buddleja globosa. ‘Nanho Purple’ (unpatented) is a semi-compact selection of Buddleja davidii var. nanhoensis. Buddleja lindleyana is a species native to China. All three parents are available in commerce.
The seeds resulting from the 2001 controlled hybridization process were harvested in fall of 2001 and germinated in a greenhouse in Raleigh, N.C. in the winter of 2002. The resulting 32 seedlings were planted in field trials in spring of 2002. These plants flowered in summer 2002, and seed was collected off of all plants and bulked. This bulk seed was germinated in a greenhouse in Raleigh, N.C. in the winter of 2003. The resulting 69 seedlings were planted in the field in spring of 2003. These plants flowered in summer 2003, and one plant, designated NC2003-7, was selected for its compact growth habit and attractive blue flowers. Open pollinated seed was collected off of NC2003-7. This bulk seed was germinated in a greenhouse in Raleigh, N.C. in the winter of 2004. The resulting 11 seedlings were planted in the field in spring of 2004. These plants flowered in summer 2004, and one plant, designated NC2004-9, was selected for its multi-branched, compact growth habit and attractive blue flowers. This original plant demonstrated characteristics identical to those subsequently expressed on other plants when propagated from stem cuttings. This single plant is the subject of the present invention ‘Blue Chip’.
The distinguishing traits of ‘Blue Chip’ are compact growth habit, multi-branched stems, gray-green leaf color, and flowers that are blue in color. The cultural requirements for ‘Blue Chip’ are well-drained soil, full sun, and moderate moisture. ‘Blue Chip’ exhibits no serious pest or disease problems known to the inventors, except for occasional spider mite infestation during periods of hot, dry weather.
The closest comparison known to the inventors is the cultivar ‘Ellen's Blue’ (unpatented). Plants and flowers of this new variety differ from ‘Ellen's Blue’. In direct comparisons of the 2 cultivars in the inventor's experimental trials, plants of ‘Blue Chip’ are consistently more compact, more highly branched, more dense, and produce less viable seed than ‘Ellen's Blue’. ‘Blue Chip’ is distinctly different from all three of its original parents.
The first asexual propagation of ‘Blue Chip’ was conducted by the inventors in fall 2004 in Raleigh, N.C., and ‘Blue Chip’ has subsequently been propagated in the same location in years 2005 and 2006. In all cases, the original plant selection was propagated asexually by softwood to semi-hardwood stem cuttings. Such cuttings root readily under mist in about 14 to 21 days, and resume normal growth. Five plants derived from stem cuttings of the variety were established in test plots at Sandhills Research Station and the Horticultural Field Laboratory in 2005, and ten additional plants derived from stem cuttings of the variety were established at the Sandhills Research Station in 2007. During all asexual propagation, the characteristics of the original plant have been maintained. Plants derived from stem cuttings exhibit characteristics identical to those of the original plant, and no aberrant phenotypes have appeared.
Test plantings and performance evaluation over three years at the Sandhills Research Station and Horticulture Field Laboratory demonstrate this variety to be relatively consistent in its characteristics even under the different growing conditions associated with yearly climatic variation.
Plants of the new variety are only moderately vigorous after establishment in the field, being less vigorous and more compact than most cultivars of butterfly bush. Young plants have averaged about 0.4 meters of growth per year. Plants are spreading in growth habit. Flowering occurs in the first year of growth on newly formed wood. The inflorescence is a simple panicle, and shows a blue flower color. Flowering usually begins in late May to early June in Jackson Springs, N.C., and continues throughout the growing season until the first freeze event in October or November. An individual inflorescence flowers for about 7-10 days, depending on temperature, but new flowers are made during the entire growing season. Fertility of flowers is low, and the new cultivar sets very few seed, an asset-in landscape settings.
‘Blue Chip’ is distinguished from other related known cultivars based on the unique combination of traits including compact growth habit, multiple-branched stems, and blue flower color.
The new variety has been named the BLUE CHIP cultivar. No public sale of ‘Blue Chip’ has yet taken place at the time of application.